Actually, probably any one of these will render most XHTML.
The question is, Can it do the simple style sheet we also must generate?
The web interface takes the canonical XML from the archive,
along with related link, style, and program files,
transforms it into a target syntax or stream, and delivers it to the user.
Is part of that sniffing for non-compliant behavior by the user's browser?
I would say no.
Just deliver HTML4.latest in XHTML form (no embedded style or scripts),
or XML and related files if the user wants to work with the raw material
personally.
With e-mail as the source, even with tables and basic links,
I bet we won't have much trouble at all, even using a simple style sheet.